Introduce WorkflowInvocationHandler

Signed-off-by: Ricardo Zanini <ricardozanini@gmail.com>

Author: ricardozanini

fluent/agentic-langchain4j/pom.xml

@@ -16,7 +16,7 @@
     <dependencies>
         <dependency>
             <groupId>io.serverlessworkflow</groupId>
-            <artifactId>serverlessworkflow-experimental-types</artifactId>
+            <artifactId>serverlessworkflow-experimental-agentic</artifactId>
         </dependency>
         <dependency>
             <groupId>io.serverlessworkflow</groupId>

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/AbstractAgentService.java

@@ -16,8 +16,12 @@
 package io.serverlessworkflow.fluent.agentic.langchain4j;
 
 import dev.langchain4j.agentic.cognisphere.Cognisphere;
+import dev.langchain4j.agentic.internal.AgentInstance;
+import dev.langchain4j.agentic.internal.CognisphereOwner;
 import io.serverlessworkflow.api.types.Workflow;
 import io.serverlessworkflow.fluent.agentic.AgentWorkflowBuilder;
+import io.serverlessworkflow.impl.WorkflowApplication;
+import java.lang.reflect.Proxy;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -26,8 +30,9 @@ public abstract class AbstractAgentService<T, S> implements WorkflowDefinitionBu
   // Workflow OutputAs
   private static final Function<Cognisphere, Object> DEFAULT_OUTPUT_FUNCTION = cognisphere -> null;
   // Workflow InputFrom
-  private static final Consumer<Cognisphere> DEFAULT_INIT_FUNCTION = cognisphere -> {};
+  private static final Consumer<Cognisphere> DEFAULT_INPUT_FUNCTION = cognisphere -> {};
 
+  protected final WorkflowApplication.Builder workflowExecBuilder;
   protected final AgentWorkflowBuilder workflowBuilder;
   protected final Class<T> agentServiceClass;
 
@@ -39,8 +44,18 @@ protected AbstractAgentService(String name, Class<T> agentServiceClass) {
     this.workflowBuilder =
         AgentWorkflowBuilder.workflow(name)
             .outputAs(DEFAULT_OUTPUT_FUNCTION)
-            .input(i -> i.from(DEFAULT_INIT_FUNCTION));
+            .input(i -> i.from(DEFAULT_INPUT_FUNCTION));
     this.agentServiceClass = agentServiceClass;
+    this.workflowExecBuilder = WorkflowApplication.builder();
+  }
+
+  @SuppressWarnings("unchecked")
+  public T build() {
+    return (T)
+        Proxy.newProxyInstance(
+            this.agentServiceClass.getClassLoader(),
+            new Class<?>[] {agentServiceClass, AgentInstance.class, CognisphereOwner.class},
+            new WorkflowInvocationHandler(this.workflowBuilder.build(), this.workflowExecBuilder));
   }
 
   @SuppressWarnings("unchecked")
@@ -56,6 +71,8 @@ public S beforeCall(Consumer<Cognisphere> beforeCall) {
   public S outputName(String outputName) {
     Function<Cognisphere, Object> outputFunction = cog -> cog.readState(outputName);
     this.workflowBuilder.outputAs(outputFunction);
+    this.workflowBuilder.document(
+        d -> d.metadata(m -> m.metadata(META_KEY_OUTPUTNAME, outputName)));
     return (S) this;
   }
 

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/ConditionalAgentServiceImpl.java

@@ -34,11 +34,6 @@ public static <T> ConditionalAgentService<T> builder(Class<T> agentServiceClass)
     return new ConditionalAgentServiceImpl<>(agentServiceClass);
   }
 
-  @Override
-  public T build() {
-    return null;
-  }
-
   @Override
   public ConditionalAgentService<T> subAgents(Object... agents) {
     this.workflowBuilder.tasks(t -> t.sequence(agents));

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/LoopAgentServiceImpl.java

@@ -47,11 +47,6 @@ public LoopAgentService<T> exitCondition(Predicate<Cognisphere> exitCondition) {
     return this;
   }
 
-  @Override
-  public T build() {
-    return null;
-  }
-
   @Override
   public LoopAgentService<T> subAgents(Object... agents) {
     this.loopAgentsBuilder.subAgents(agents);

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/ParallelAgentServiceImpl.java

@@ -23,8 +23,6 @@
 public class ParallelAgentServiceImpl<T> extends AbstractAgentService<T, ParallelAgentService<T>>
     implements ParallelAgentService<T> {
 
-  private ExecutorService executor;
-
   private ParallelAgentServiceImpl(Class<T> agentServiceClass) {
     super(agentServiceClass);
   }
@@ -35,15 +33,10 @@ public static <T> ParallelAgentService<T> builder(Class<T> agentServiceClass) {
 
   @Override
   public ParallelAgentService<T> executorService(ExecutorService executorService) {
-    this.executor = executorService;
+    this.workflowExecBuilder.withExecutorFactory(() -> executorService);
     return this;
   }
 
-  @Override
-  public T build() {
-    return null;
-  }
-
   @Override
   public ParallelAgentService<T> subAgents(Object... agents) {
     this.workflowBuilder.tasks(t -> t.parallel(agents));

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/SequentialAgentServiceImpl.java

@@ -31,14 +31,6 @@ public static <T> SequentialAgentServiceImpl<T> builder(Class<T> agentServiceCla
     return new SequentialAgentServiceImpl<>(agentServiceClass);
   }
 
-  @Override
-  public T build() {
-    // TODO: create a proxy of an InvocationHandler wrapping our WorkflowApplication, calling `run`
-    // on `invoke`.
-    // TODO: we pass what we built here to the runner
-    return null;
-  }
-
   @Override
   public SequentialAgentService<T> subAgents(Object... agents) {
     this.workflowBuilder.tasks(t -> t.sequence(agents));

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/WorkflowDefinitionBuilder.java

@@ -19,5 +19,7 @@
 
 public interface WorkflowDefinitionBuilder {
 
+  String META_KEY_OUTPUTNAME = "outputName";
+
   Workflow getDefinition();
 }

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/WorkflowExecutor.java

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.serverlessworkflow.fluent.agentic.langchain4j;
+
+public class WorkflowExecutor {}

fluent/agentic-langchain4j/src/main/java/io/serverlessworkflow/fluent/agentic/langchain4j/WorkflowInvocationHandler.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.serverlessworkflow.fluent.agentic.langchain4j;
+
+import dev.langchain4j.agentic.cognisphere.Cognisphere;
+import dev.langchain4j.agentic.cognisphere.CognisphereAccess;
+import dev.langchain4j.agentic.cognisphere.CognisphereKey;
+import dev.langchain4j.agentic.cognisphere.CognisphereRegistry;
+import dev.langchain4j.agentic.internal.AgentInstance;
+import dev.langchain4j.agentic.internal.CognisphereOwner;
+import io.serverlessworkflow.api.types.Workflow;
+import io.serverlessworkflow.impl.WorkflowApplication;
+import java.lang.reflect.Method;
+
+public class WorkflowInvocationHandler implements CognisphereOwner {
+
+  private final Workflow workflow;
+  private final WorkflowApplication.Builder workflowApplicationBuilder;
+  private Cognisphere cognisphere;
+
+  WorkflowInvocationHandler(
+      Workflow workflow, WorkflowApplication.Builder workflowApplicationBuilder) {
+    this.workflow = workflow;
+    this.workflowApplicationBuilder = workflowApplicationBuilder;
+  }
+
+  @Override
+  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+    // outputName
+    if (method.getDeclaringClass() == AgentInstance.class) {
+      return switch (method.getName()) {
+        case "outputName" ->
+            this.workflow
+                .getDocument()
+                .getMetadata()
+                .getAdditionalProperties()
+                .get(WorkflowDefinitionBuilder.META_KEY_OUTPUTNAME);
+        default ->
+            throw new UnsupportedOperationException(
+                "Unknown method on AgentInstance class : " + method.getName());
+      };
+    }
+    // withCognisphere
+    if (method.getDeclaringClass() == CognisphereOwner.class) {
+      // Ingest the workflow input as a Cognisphere object
+      // Later, retrieve it and start the workflow with it as input.
+      return switch (method.getName()) {
+        case "withCognisphere" -> this.withCognisphere((Cognisphere) args[0]);
+        default ->
+            throw new UnsupportedOperationException(
+                "Unknown method on CognisphereOwner class : " + method.getName());
+      };
+    }
+    // getCognisphere
+    // evictCognisphere
+    if (method.getDeclaringClass() == CognisphereAccess.class) {
+      return switch (method.getName()) {
+        case "getCognisphere" ->
+            CognisphereRegistry.get(
+                new CognisphereKey(this.workflow.getDocument().getName(), args[0]));
+        case "evictCognisphere" ->
+            CognisphereRegistry.evict(
+                new CognisphereKey(this.workflow.getDocument().getName(), args[0]));
+        default ->
+            throw new UnsupportedOperationException(
+                "Unknown method on CognisphereAccess class : " + method.getName());
+      };
+    }
+
+    // invoke
+    return null;
+  }
+
+  @Override
+  public CognisphereOwner withCognisphere(Cognisphere cognisphere) {
+    this.cognisphere = cognisphere;
+    return this;
+  }
+}

fluent/pom.xml

@@ -54,6 +54,11 @@
                 <artifactId>serverlessworkflow-fluent-agentic-langchain4j</artifactId>
                 <version>${project.version}</version>
             </dependency>
+            <dependency>
+                <groupId>io.serverlessworkflow</groupId>
+                <artifactId>serverlessworkflow-experimental-agentic</artifactId>
+                <version>${project.version}</version>
+            </dependency>
             <dependency>
                 <groupId>io.serverlessworkflow</groupId>
                 <artifactId>serverlessworkflow-fluent-agentic</artifactId>